An electric vehicle (EV), also referred to as an electric drive vehicle, is a vehicle which uses one or more electric motors for propulsion. These vehicles are powered using electrical energy. A plug-in electric vehicle (PEV) is a type of EV with batteries that can be recharged by connecting a plug to an electric power source (such as wall sockets). The electricity may then be stored onboard the vehicle using a battery, flywheel, supercapacitor or fuel cell.
A Plug-in Hybrid Electric Vehicle (PHEV) is special type of PEV that combines a conventional Internal Combustion Engine (ICE) with an electric propulsion system. While there is a provision for fossil fuel use in PHEV's, they distinguish over Hybrid Electric Vehicles (HEV) in that the internal combustion engine alone is not the only source for recharging the battery—the recharging can easily be accomplished by plugging into or otherwise connecting to an electrical power source.
Most EVs on the road today are passenger cars, but there are also PHEV versions of commercial passenger vans, utility trucks, school buses, motorcycles, scooters, and military vehicles. In this document, the term “vehicle” is used to represent any vehicle that can be electrically powered and externally charged.
Generally, the cost for electricity to power electric vehicles has been estimated at less than one quarter of the cost of gasoline. As has been much appreciated, compared to conventional vehicles, EVs can reduce air pollution, dependence on petroleum, and greenhouse gas emissions that contribute to global warming. Even plug-in hybrids use no fossil fuel during their all-electric range if their batteries are charged from nuclear or renewable energy sources.
Other benefits include improved national energy security (due to less dependence on foreign oil), fewer fill-ups at the filling station, the convenience of home recharging, opportunities to provide emergency backup power in the home, and vehicle to grid applications. Given the benefits of EVs, major automobile manufacturers have scheduled, or announced an intention to schedule, the production of EV automobiles in coming years.
Generally, the frequency of recharging an EV is determined by the average distance driven per day and the energy efficiency (miles per unit of energy) of the vehicle. However, the vehicle owners may not get the necessary electrical energy at the best price at the location when they want to recharge because utility companies, to protect themselves from widely fluctuating costs and to reduce peak demands, have started introducing various time-based pricing mechanisms such as Time Of Use (TOU), Critical Peak Pricing (CPP), Real Time Pricing (RTP) and Peak Load Reduction Credits (PLRC) etc.